126 PROCEEDINGS OF THE SCIENTIFIC ASSOCIATION. 
off inflammable gas. A large increase of volume also takes 
place when it is heated in a tube. The ash is light in colour, 
and appears to consist chiefly of yellow clay. 
The mineral is completely soluble in bisulphide of carbon, 
benzol, chloroform and in warm oil of turpentine, and forms 
with these solvents a black varnish which on exposure dries 
up to a brittle residue of great brilliancy. It is also partly 
soluble in rock oil. Boiled with alcohol, the latter becomes 
yellow, and on evaporation deposits a small quantity of 
yellow oily matter. The residue, after extraction with 
alcohol, partly dissolves in ether, forming a reddish brown 
solution exhibiting a strong bluish-green fluorescence, and 
yielding on evaporation a dark residue of tarry consistence. 
Boiling solutions of potash and potassium carbonate, even 
when concentrated, do not apparently dissolve or change the 
substance. 
The melting-point of the mineral could not be determined, 
since it never becomes actually fluid under the influence 
of heat. Moreover, it bears without visible alteration a 
temperature far exceeding the melting-point of ordinary 
hard asphalt, namely, 100°C. Fragments, placed in a tube 
immersed in a bath of heated oil of vitriol, only showed 
incipient softening at 265°C, and little or no further change 
was produced even when the boiling-point of the oil of 
vitriol had been exceeded, and a temperature of 340°C 
reached — this being the greatest heat a mercurial thermo- 
meter can be subjected to with safety. 
Quantitative operations gave the following results : — 
Specific gravity ,. ... 1*1482 
Weight of cubic foot 71*597 lbs. 
Space occupied by solid ton ... 31*0.00 cub., ft. 
